diff --git a/com.google.eclipse.protobuf.test/src/com/google/eclipse/protobuf/conversion/FLOATValueConverter_toValue_Test.java b/com.google.eclipse.protobuf.test/src/com/google/eclipse/protobuf/conversion/DOUBLEValueConverter_toValue_Test.java
similarity index 67%
rename from com.google.eclipse.protobuf.test/src/com/google/eclipse/protobuf/conversion/FLOATValueConverter_toValue_Test.java
rename to com.google.eclipse.protobuf.test/src/com/google/eclipse/protobuf/conversion/DOUBLEValueConverter_toValue_Test.java
index 03e58d8..6804161 100644
--- a/com.google.eclipse.protobuf.test/src/com/google/eclipse/protobuf/conversion/FLOATValueConverter_toValue_Test.java
+++ b/com.google.eclipse.protobuf.test/src/com/google/eclipse/protobuf/conversion/DOUBLEValueConverter_toValue_Test.java
@@ -8,6 +8,7 @@
  */
 package com.google.eclipse.protobuf.conversion;
 
+import static java.lang.Double.*;
 import static java.util.Arrays.asList;
 import static org.hamcrest.core.IsEqual.equalTo;
 import static org.junit.Assert.assertThat;
@@ -24,45 +25,47 @@
 import com.google.eclipse.protobuf.junit.core.XtextRule;
 
 /**
- * Tests for <code>{@link FLOATValueConverter#toValue(String, INode)}</code>.
+ * Tests for <code>{@link DOUBLEValueConverter#toValue(String, INode)}</code>.
  *
  * @author alruiz@google.com (Alex Ruiz)
  */
 @RunWith(Parameterized.class)
-public class FLOATValueConverter_toValue_Test {
+public class DOUBLEValueConverter_toValue_Test {
 
   @Rule public XtextRule xtext = new XtextRule();
 
   private final String input;
-  private final Float expected;
+  private final Double expected;
 
   @Parameters
   public static Collection<Object[]> parameters() {
     return asList(new Object[][] {
-      { "52e3", 52e3F },
-      { "52E3", 52e3F },
-      { "6e-3", 0.006F },
-      { "6.8", 6.8F },
-      { "-3.1", -3.1F },
-      { ".3", 0.3F }
+      { "52e3", 52e3D },
+      { "52E3", 52e3D },
+      { "6e-3", 0.006D },
+      { "6.8", 6.8D },
+      { "-3.1", -3.1D },
+      { ".3", 0.3D },
+      { "nan", NaN },
+      { "inf", POSITIVE_INFINITY }
     });
   }
 
-  public FLOATValueConverter_toValue_Test(String input, Float expected) {
+  public DOUBLEValueConverter_toValue_Test(String input, Double expected) {
     this.input = input;
     this.expected = expected;
   }
 
-  private FLOATValueConverter converter;
+  private DOUBLEValueConverter converter;
   private INode node;
 
   @Before public void setUp() {
     node = mock(INode.class);
-    converter = xtext.injector().getInstance(FLOATValueConverter.class);
+    converter = xtext.injector().getInstance(DOUBLEValueConverter.class);
   }
 
   @Test public void should_parse_hexadecimal_number() {
-    Float value = converter.toValue(input, node);
+    Double value = converter.toValue(input, node);
     assertThat(value, equalTo(expected));
   }
 }
diff --git a/com.google.eclipse.protobuf.test/src/com/google/eclipse/protobuf/conversion/FLOATValueConverter_toValue_withInvalidInput_Test.java b/com.google.eclipse.protobuf.test/src/com/google/eclipse/protobuf/conversion/FLOATValueConverter_toValue_withInvalidInput_Test.java
index a2957f4..7dc34e3 100644
--- a/com.google.eclipse.protobuf.test/src/com/google/eclipse/protobuf/conversion/FLOATValueConverter_toValue_withInvalidInput_Test.java
+++ b/com.google.eclipse.protobuf.test/src/com/google/eclipse/protobuf/conversion/FLOATValueConverter_toValue_withInvalidInput_Test.java
@@ -22,7 +22,7 @@
 import com.google.eclipse.protobuf.junit.core.XtextRule;
 
 /**
- * Tests for <code>{@link FLOATValueConverter#toValue(String, INode)}</code>.
+ * Tests for <code>{@link DOUBLEValueConverter#toValue(String, INode)}</code>.
  *
  * @author alruiz@google.com (Alex Ruiz)
  */
@@ -31,12 +31,12 @@
   @Rule public XtextRule xtext = new XtextRule();
   @Rule public ExpectedException thrown = none();
 
-  private FLOATValueConverter converter;
+  private DOUBLEValueConverter converter;
   private INode node;
 
   @Before public void setUp() {
     node = mock(INode.class);
-    converter = xtext.injector().getInstance(FLOATValueConverter.class);
+    converter = xtext.injector().getInstance(DOUBLEValueConverter.class);
   }
 
   @Test public void should_throw_error_if_input_is_null() {
diff --git a/com.google.eclipse.protobuf.test/src/com/google/eclipse/protobuf/scoping/Descriptor_fileOptions_Test.java b/com.google.eclipse.protobuf.test/src/com/google/eclipse/protobuf/scoping/Descriptor_availableOptionPropertiesFor_Test.java
similarity index 81%
rename from com.google.eclipse.protobuf.test/src/com/google/eclipse/protobuf/scoping/Descriptor_fileOptions_Test.java
rename to com.google.eclipse.protobuf.test/src/com/google/eclipse/protobuf/scoping/Descriptor_availableOptionPropertiesFor_Test.java
index 72b65ed..7ee78d2 100644
--- a/com.google.eclipse.protobuf.test/src/com/google/eclipse/protobuf/scoping/Descriptor_fileOptions_Test.java
+++ b/com.google.eclipse.protobuf.test/src/com/google/eclipse/protobuf/scoping/Descriptor_availableOptionPropertiesFor_Test.java
@@ -11,32 +11,35 @@
 import static com.google.eclipse.protobuf.junit.matchers.PropertyHasType.hasType;
 import static org.hamcrest.core.IsEqual.equalTo;
 import static org.junit.Assert.assertThat;
+import static org.mockito.Mockito.mock;
 
 import java.util.*;
 
+import org.eclipse.emf.ecore.EObject;
 import org.junit.*;
 
 import com.google.eclipse.protobuf.junit.core.XtextRule;
-import com.google.eclipse.protobuf.protobuf.Property;
+import com.google.eclipse.protobuf.protobuf.*;
 
 /**
- * Tests for <code>{@link ProtoDescriptor#fileOptions()}</code>.
+ * Tests for <code>{@link ProtoDescriptor#availableOptionPropertiesFor(EObject)}</code>.
  *
  * @author alruiz@google.com (Alex Ruiz)
  */
 @Ignore("This test requires to be executed as a 'JUnit plug-in test'. I haven't found a way to register PlatformURLHandler with the JVM")
-public class Descriptor_fileOptions_Test {
+public class Descriptor_availableOptionPropertiesFor_Test {
 
   @Rule public XtextRule xtext = new XtextRule();
 
   private ProtoDescriptor descriptor;
-
+  
   @Before public void setUp() {
     descriptor = xtext.getInstanceOf(ProtoDescriptorProvider.class).get();
   }
 
   @Test public void should_return_all_file_options() {
-    Map<String, Property> fileOptions = mapByName(descriptor.fileOptions());
+    Protobuf optionContainer = mock(Protobuf.class);
+    Map<String, Property> fileOptions = mapByName(descriptor.availableOptionPropertiesFor(optionContainer));
     assertThat(fileOptions.get("java_package"), hasType("string"));
     assertThat(fileOptions.get("java_outer_classname"), hasType("string"));
     assertThat(fileOptions.get("java_multiple_files"), hasType("bool"));
diff --git a/com.google.eclipse.protobuf.ui/META-INF/MANIFEST.MF b/com.google.eclipse.protobuf.ui/META-INF/MANIFEST.MF
index fd2b236..da7e2d6 100644
--- a/com.google.eclipse.protobuf.ui/META-INF/MANIFEST.MF
+++ b/com.google.eclipse.protobuf.ui/META-INF/MANIFEST.MF
@@ -2,7 +2,7 @@
 Bundle-ManifestVersion: 2
 Bundle-Name: %Bundle-Name
 Bundle-Vendor: %Bundle-Vendor
-Bundle-Version: 1.0.8.qualifier
+Bundle-Version: 1.0.9.qualifier
 Bundle-SymbolicName: com.google.eclipse.protobuf.ui; singleton:=true
 Bundle-ActivationPolicy: lazy
 Require-Bundle: com.google.eclipse.protobuf;visibility:=reexport,
diff --git a/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/quickfix/Messages.java b/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/quickfix/Messages.java
new file mode 100644
index 0000000..03ea039
--- /dev/null
+++ b/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/quickfix/Messages.java
@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2011 Google Inc.
+ * 
+ * All rights reserved. This program and the accompanying materials are made
+ * available under the terms of the Eclipse Public License v1.0 which
+ * accompanies this distribution, and is available at
+ * 
+ * http://www.eclipse.org/legal/epl-v10.html
+ */
+package com.google.eclipse.protobuf.ui.quickfix;
+
+import org.eclipse.osgi.util.NLS;
+
+/**
+ * @author alruiz@google.com (Alex Ruiz)
+ */
+public class Messages extends NLS {
+  
+  public static String changeToProto2;
+  public static String changeToProto2Label;
+  
+  static {
+    Class<Messages> targetType = Messages.class;
+    NLS.initializeMessages(targetType.getName(), targetType);
+  }
+
+  private Messages() {}
+}
diff --git a/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/quickfix/Messages.properties b/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/quickfix/Messages.properties
new file mode 100644
index 0000000..54e5126
--- /dev/null
+++ b/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/quickfix/Messages.properties
@@ -0,0 +1,2 @@
+changeToProto2=Change syntax to "proto2".
+changeToProto2Label=Change syntax to "proto2"
diff --git a/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/quickfix/ProtobufQuickAssistProcessor.java b/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/quickfix/ProtobufQuickAssistProcessor.java
index 15aa610..a5dc287 100644
--- a/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/quickfix/ProtobufQuickAssistProcessor.java
+++ b/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/quickfix/ProtobufQuickAssistProcessor.java
@@ -10,6 +10,7 @@
 package com.google.eclipse.protobuf.ui.quickfix;
 
 import static java.util.Arrays.asList;
+import static java.util.Collections.emptyList;
 
 import com.google.inject.Inject;
 
@@ -27,10 +28,21 @@
 
   @Inject private SpellingCorrectionProcessor spellingCorrectionProcessor;
 
-  @Override public ICompletionProposal[] computeQuickAssistProposals(IQuickAssistInvocationContext invocationContext) {
+  @Override public ICompletionProposal[] computeQuickAssistProposals(IQuickAssistInvocationContext context) {
     List<ICompletionProposal> proposals = new ArrayList<ICompletionProposal>();
-    proposals.addAll(asList(spellingCorrectionProcessor.computeQuickAssistProposals(invocationContext)));
-    proposals.addAll(asList(super.computeQuickAssistProposals(invocationContext)));
+    proposals.addAll(spellingFixes(context));
+    proposals.addAll(asList(super.computeQuickAssistProposals(context)));
     return proposals.toArray(new ICompletionProposal[proposals.size()]);
   }
+  
+  private List<ICompletionProposal> spellingFixes(IQuickAssistInvocationContext context) {
+    ICompletionProposal[] spellingFixes = spellingCorrectionProcessor.computeQuickAssistProposals(context);
+    if (spellingFixes.length == 0) return emptyList();
+    if (spellingFixes.length == 1 && isNoCompletionsProposal(spellingFixes[0])) return emptyList();
+    return asList(spellingFixes);
+  }
+  
+  private boolean isNoCompletionsProposal(ICompletionProposal p) {
+    return p.getClass().getSimpleName().equals("NoCompletionsProposal");
+  }
 }
diff --git a/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/quickfix/ProtobufQuickfixProvider.java b/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/quickfix/ProtobufQuickfixProvider.java
index 59fc306..04f7973 100644
--- a/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/quickfix/ProtobufQuickfixProvider.java
+++ b/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/quickfix/ProtobufQuickfixProvider.java
@@ -1,29 +1,42 @@
 /*
  * Copyright (c) 2011 Google Inc.
- *
- * All rights reserved. This program and the accompanying materials are made available under the terms of the Eclipse
- * Public License v1.0 which accompanies this distribution, and is available at
- *
+ * 
+ * All rights reserved. This program and the accompanying materials are made
+ * available under the terms of the Eclipse Public License v1.0 which
+ * accompanies this distribution, and is available at
+ * 
  * http://www.eclipse.org/legal/epl-v10.html
  */
 package com.google.eclipse.protobuf.ui.quickfix;
 
-import org.eclipse.xtext.ui.editor.quickfix.DefaultQuickfixProvider;
+import static com.google.eclipse.protobuf.ui.quickfix.Messages.*;
+import static com.google.eclipse.protobuf.validation.ProtobufJavaValidator.SYNTAX_IS_NOT_PROTO2_ERROR_CODE;
+
+import com.google.eclipse.protobuf.protobuf.Syntax;
+import com.google.eclipse.protobuf.ui.labeling.Images;
+import com.google.inject.Inject;
+
+import org.eclipse.emf.ecore.EObject;
+import org.eclipse.xtext.ui.editor.model.edit.*;
+import org.eclipse.xtext.ui.editor.quickfix.*;
+import org.eclipse.xtext.validation.Issue;
 
 /**
  * @author alruiz@google.com (Alex Ruiz)
  */
 public class ProtobufQuickfixProvider extends DefaultQuickfixProvider {
 
-//	@Fix(MyJavaValidator.INVALID_NAME)
-//	public void capitalizeName(final Issue issue, IssueResolutionAcceptor acceptor) {
-//		acceptor.accept(issue, "Capitalize name", "Capitalize the name.", "upcase.png", new IModification() {
-//			public void apply(IModificationContext context) throws BadLocationException {
-//				IXtextDocument xtextDocument = context.getXtextDocument();
-//				String firstLetter = xtextDocument.get(issue.getOffset(), 1);
-//				xtextDocument.replace(issue.getOffset(), 1, firstLetter.toUpperCase());
-//			}
-//		});
-//	}
-
+  @Inject private Images images;
+  
+  @Fix(SYNTAX_IS_NOT_PROTO2_ERROR_CODE) 
+  public void makeSyntaxProto2(final Issue issue, IssueResolutionAcceptor acceptor) {
+    String image = images.imageFor(Syntax.class);
+    acceptor.accept(issue, changeToProto2Label, changeToProto2, image, new ISemanticModification() {
+      public void apply(EObject element, IModificationContext context) throws Exception {
+        if (!(element instanceof Syntax)) return;
+        Syntax syntax = (Syntax) element;
+        syntax.setName("proto2");
+      }
+    });
+  }
 }
diff --git a/com.google.eclipse.protobuf/META-INF/MANIFEST.MF b/com.google.eclipse.protobuf/META-INF/MANIFEST.MF
index 06792c5..21189b7 100644
--- a/com.google.eclipse.protobuf/META-INF/MANIFEST.MF
+++ b/com.google.eclipse.protobuf/META-INF/MANIFEST.MF
@@ -3,7 +3,7 @@
 Eclipse-ExtensibleAPI: true
 Bundle-Name: %Bundle-Name
 Bundle-Vendor: %Bundle-Vendor
-Bundle-Version: 1.0.8.qualifier
+Bundle-Version: 1.0.9.qualifier
 Bundle-SymbolicName: com.google.eclipse.protobuf; singleton:=true
 Bundle-ActivationPolicy: lazy
 Require-Bundle: org.eclipse.xtext,
diff --git a/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/Protobuf.xtext b/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/Protobuf.xtext
index 84ba83c..6c6c4d3 100644
--- a/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/Protobuf.xtext
+++ b/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/Protobuf.xtext
@@ -106,7 +106,7 @@
   name=Name ':' value=SimpleRef;
 
 SimpleRef:
-	LiteralRef | BooleanRef | NumberRef | StringRef | Nan;
+	LiteralRef | BooleanRef | NumberRef | StringRef;
 
 LiteralRef:
   literal=[Literal];
@@ -119,7 +119,7 @@
   | false;
 
 NumberRef:
-  HexRef | LongRef | FloatRef;
+  HexRef | LongRef | DoubleRef;
 
 HexRef:
   hex=HEX;
@@ -130,11 +130,11 @@
 terminal LONG returns ecore::ELong:
   ('-')? (NUMBER)+;
 
-FloatRef:
-  float=FLOAT;
+DoubleRef:
+  double=DOUBLE;
 
-terminal FLOAT returns ecore::EFloat:
-  ('-')? (NUMBER)* ('.' (NUMBER)+)? (('e'|'E')('-')? (NUMBER)+)?;
+terminal DOUBLE returns ecore::EDouble:
+  (('-')? (NUMBER)* ('.' (NUMBER)+)? (('e'|'E')('-')? (NUMBER)+)?) | 'nan' | 'inf';
 
 StringRef:
   string=STRING;
@@ -143,13 +143,11 @@
   SL_STRING (SL_STRING)*;
 
 terminal SL_STRING:
-  '"' ('\\' ('b' | 't' | 'n' | 'f' | 'r' | 'u' | '"' | "'" | '\\' | UNICODE_OCTAL) | !('\\' | '"'))* '"' (WS)*;
+  '"' ('\\' ('b' | 't' | 'n' | 'f' | 'r' | 'u' | '"' | "'" | '\\' | UNICODE_OCTAL) | !('\\' | '"'))* '"' (WS)* |
+  "'" ('\\' ('b' | 't' | 'n' | 'f' | 'r' | 'u' | '"' | "'" | '\\' | UNICODE_OCTAL) | !('\\' | "'"))* "'" (WS)*;
 
 terminal UNICODE_OCTAL:
   ('0'..'3')('0'..'7')('0'..'7');
-  
-Nan:
-  number='nan';
 
 Enum:
   'enum' name=Name '{'
diff --git a/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/conversion/FLOATValueConverter.java b/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/conversion/DOUBLEValueConverter.java
similarity index 72%
rename from com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/conversion/FLOATValueConverter.java
rename to com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/conversion/DOUBLEValueConverter.java
index 930b070..cec6067 100644
--- a/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/conversion/FLOATValueConverter.java
+++ b/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/conversion/DOUBLEValueConverter.java
@@ -8,6 +8,8 @@
  */
 package com.google.eclipse.protobuf.conversion;
 
+import static java.lang.Double.*;
+import static java.lang.Double.NaN;
 import static org.eclipse.xtext.util.Strings.isEmpty;
 
 import org.eclipse.xtext.conversion.ValueConverterException;
@@ -15,11 +17,11 @@
 import org.eclipse.xtext.nodemodel.INode;
 
 /**
- * Converts floating-point numbers to {@code float}s.
+ * Converts floating-point numbers to {@code double}s.
  *
  * @author alruiz@google.com (Alex Ruiz)
  */
-public class FLOATValueConverter extends AbstractLexerBasedConverter<Float> {
+public class DOUBLEValueConverter extends AbstractLexerBasedConverter<Double> {
 
   /**
    * Creates an {@code float} from the given input, if the given input represents a floating-point number.
@@ -29,16 +31,18 @@
    * @throws ValueConverterException if the given input is {@code null}, empty or does not represent a floating-point 
    * number.
    */
-  public Float toValue(String string, INode node) throws ValueConverterException {
-    if (isEmpty(string)) throw new ValueConverterException("Couldn't convert empty string to float.", node, null);
+  public Double toValue(String string, INode node) throws ValueConverterException {
+    if (isEmpty(string)) throw new ValueConverterException("Couldn't convert empty string to double.", node, null);
+    if ("nan".equals(string)) return NaN;
+    if ("inf".equals(string)) return POSITIVE_INFINITY;
     try {
-      return Float.parseFloat(string);
+      return Double.parseDouble(string);
     } catch (NumberFormatException e) {
       throw parsingError(string, node, e);
     }
   }
 
   private ValueConverterException parsingError(String string, INode node, Exception cause) {
-    return new ValueConverterException("Couldn't convert '" + string + "' to float.", node, cause);
+    return new ValueConverterException("Couldn't convert '" + string + "' to double.", node, cause);
   }
 }
diff --git a/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/conversion/ProtobufTerminalConverters.java b/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/conversion/ProtobufTerminalConverters.java
index e4ac026..d778e94 100644
--- a/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/conversion/ProtobufTerminalConverters.java
+++ b/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/conversion/ProtobufTerminalConverters.java
@@ -18,14 +18,14 @@
  */
 public class ProtobufTerminalConverters extends DefaultTerminalConverters {
 
-  @Inject private FLOATValueConverter floatValueConverter;
+  @Inject private DOUBLEValueConverter doubleValueConverter;
   @Inject private HEXValueConverter hexValueConverter;
   @Inject private LONGValueConverter longValueConverter;
   @Inject private STRINGValueConverter stringValueConverter;
   
-  @ValueConverter(rule = "FLOAT")
-  public IValueConverter<Float> FLOAT() {
-    return floatValueConverter;
+  @ValueConverter(rule = "DOUBLE")
+  public IValueConverter<Double> DOUBLE() {
+    return doubleValueConverter;
   }
   
   @ValueConverter(rule = "HEX")
diff --git a/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/conversion/STRINGValueConverter.java b/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/conversion/STRINGValueConverter.java
index 63c5f96..ae23a29 100644
--- a/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/conversion/STRINGValueConverter.java
+++ b/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/conversion/STRINGValueConverter.java
@@ -41,7 +41,7 @@
   public String toValue(String string, INode node) throws ValueConverterException {
     if (string == null) return null;
     try {
-      String clean = removeLineBreaksFrom(string);
+      String clean = removeLineBreaksFrom(string).trim();
       return convertToJavaString(clean.substring(1, clean.length() - 1), true);
     } catch (IllegalArgumentException e) {
       throw parsingError(string, node, e);
diff --git a/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/scoping/OptionType.java b/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/scoping/OptionType.java
index ce32976..2c75f54 100644
--- a/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/scoping/OptionType.java
+++ b/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/scoping/OptionType.java
@@ -21,7 +21,7 @@
  */
 enum OptionType {
   FILE("FileOptions"), MESSAGE("MessageOptions"), FIELD("FieldOptions"), ENUM("EnumOptions"),
-      ENUM_LITERAL("EnumValueOptions"), SERVICE("ServiceOptions"), RPC("MethodOptions");
+      LITERAL("EnumValueOptions"), SERVICE("ServiceOptions"), RPC("MethodOptions");
 
   private static final Map<Class<?>, OptionType> OPTION_TYPES_BY_CONTAINER = new HashMap<Class<?>, OptionType>();
 
@@ -48,4 +48,4 @@
     }
     return null;
   }
-}
\ No newline at end of file
+}
diff --git a/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/scoping/ProtoDescriptor.java b/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/scoping/ProtoDescriptor.java
index 984b28f..af6225f 100644
--- a/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/scoping/ProtoDescriptor.java
+++ b/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/scoping/ProtoDescriptor.java
@@ -133,11 +133,12 @@
   }
 
   /**
-   * Returns the options available for the given option or option container. For example, if the given object is an
-   * <code>{@link Enum}</code>, this method will return <code>{@link #enumOptions()}</code>.
-   * @param o an option or an option container.
+   * Returns the options available for the given option or option container. The returned options are defined in
+   * {@code google/protobuf/descriptor.proto} (more details can be found
+   * <a href=http://code.google.com/apis/protocolbuffers/docs/proto.html#options" target="_blank">here</a>.)
+   * @param o the given option or option container.
    * @return the options available for the given option or option container, or an empty collection if the are not any
-   * options available for the given option container.
+   * options available.
    */
   public Collection<Property> availableOptionPropertiesFor(EObject o) {
     EObject target = o;
diff --git a/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/util/Properties.java b/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/util/Properties.java
index 625ca65..df6ed1c 100644
--- a/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/util/Properties.java
+++ b/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/util/Properties.java
@@ -55,6 +55,11 @@
     return isScalarType(p, BOOL);
   }
 
+  /**
+   * Indicates whether the given property can accept "nan" as its default value.
+   * @param p the given property.
+   * @return {@code true} if the given property  can accept "nan" as its default value, {@code false} otherwise.
+   */
   public boolean mayBeNan(Property p) {
     String typeName = typeNameOf(p);
     return FLOAT.hasValue(typeName) || DOUBLE.hasValue(typeName);
diff --git a/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/validation/ProtobufJavaValidator.java b/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/validation/ProtobufJavaValidator.java
index 9de1574..1ede6e7 100644
--- a/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/validation/ProtobufJavaValidator.java
+++ b/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/validation/ProtobufJavaValidator.java
@@ -30,6 +30,9 @@
  */
 public class ProtobufJavaValidator extends AbstractProtobufJavaValidator {
 
+  public static final String SYNTAX_IS_NOT_PROTO2_ERROR_CODE = "syntaxIsNotProto2";
+  public static final String TAG_NUMBER_IS_NOT_UNIQUE_ERROR_CODE = "tagNumberIsNotUnique";
+
   @Inject private FieldOptions fieldOptions;
   @Inject private ImportUriResolver uriResolver;
   @Inject private IQualifiedNameProvider qualifiedNameProvider;
@@ -71,7 +74,7 @@
     String name = syntax.getName();
     if ("proto2".equals(name)) return;
     String msg = (name == null) ? expectedSyntaxIdentifier : format(unrecognizedSyntaxIdentifier, name);
-    error(msg, SYNTAX__NAME);
+    error(msg, syntax, SYNTAX__NAME, SYNTAX_IS_NOT_PROTO2_ERROR_CODE);
   }
 
   @Check public void checkTagNumberIsUnique(Field field) {
@@ -87,7 +90,7 @@
         if (other.getIndex() != index) continue;
         QualifiedName messageName = qualifiedNameProvider.getFullyQualifiedName(message);
         String msg = format(fieldNumberAlreadyUsed, index, messageName.toString(), other.getName());
-        error(msg, FIELD__INDEX);
+        error(msg, field, FIELD__INDEX, TAG_NUMBER_IS_NOT_UNIQUE_ERROR_CODE);
         break;
       }
     }